The communications industry is rapidly changing to adjust to emerging technologies and ever increasing customer demand. This customer demand for new applications and increased performance of existing applications is driving communications network and system providers to employ networks and systems having greater speed and capacity (e.g., greater bandwidth). In trying to achieve these goals, a common approach taken by many communications providers is to use packet switching technology.
In a Provider Backbone Bridging architecture, customer networks (e.g., using 802.1q bridging) are aggregated into Provider Bridged networks (e.g., using 802.1ad). These, in turn, are aggregated into Provider Backbone Bridging networks which use the 802.1 ah frame format. The frame format employs a MAC tunneling encapsulation scheme for tunneling customer Ethernet frames within provider Ethernet frames across the Provider Backbone Bridging network. A VLAN ID is used to segregate the backbone into broadcast domains or topologies, and a 24-bit service identifier (I-SID) is defined and used to associate a given customer MAC frame with a provider service instance.